1. Field of the Invention
The present invention relates to a skin covered foamed plastic seat, to be used, for example, for car seat cushions and seat backs.
2. Description of the Background Art
Car seat cushions and seat backs have been made of a pad member covered by a skin cover. The pad member and the skin cover were used to be manufactured separately and combined together later, but it has become fashionable to manufacture a skin covered pad member altogether by making the foamed plastic inside the skin cover placed over a molding surface, so that the process of combining at later time may be omitted.
This is done by placing a skin cover over a lower mold and assembling the lower mold with an upper mold such that edges of the skin cover is pinched between parting lines between the upper mold and the lower mold, and then pouring liquid foam resin into a space between the upper mold and the lower mold which will become a pad member covered with the skin cover after the foaming process.
One of the difficult problem encountered in this manufacturing process is the appearance of creases on the surface of the skin cover at those portion placed in the parting lines.
FIG. 1 shows a conventional situation at a portion around a parting line in a mold for manufacturing a skin covered foamed plastic seat in which a parting line is formed by a portion 1a of a lower mold 1 and a portion 2a of an upper mold 2 which together pinch the edge of a skin cover 3 placed over the lower mold 1. The skin cover 3 is comprised of a surface skin 3a and a wadding 3b made of a foamed slav-urethane which is air permeable and impregnable. Thus, when the liquid foam resin is poured in, the wadding 3b is impregnated with the liquid foam resin which will subsequently stiffen as the foaming process progresses, and those portion of the skin cover 3 placed in the parting line will retain its pressed form, resulting in appearance of the creases which are difficult to remove afterwards and which damages the value of the skin covered foamed plastic seat as a product for sale.